Hantavirus: History, species, signs and symptoms, diagnosis, transmission, epidemiology, treatment, prevention, when to see a doctor.

While the world is taking different measures to over come the deadly Coronavirus outbreak, here comes another virus called Hantavirus.

Known History

Hantavirus was first recognized as an infectious disease in the early 1950s when a cluster of 3,000 United Nation troops stationed in Korea was struck by a mysterious illness. Ten to fifteen percent of those infected perished,and though the exact etiologic agent was not discovered for two decades, it was suspected that rodents served as the main epidemiologic vector. Infection was associated with fever, hypotension, renal failure, thrombocytopenia, and disseminated intravascular coagulation (DIC). The clinical syndrome became known as hemorrhagic fever with renal syndrome (HFRS), formerly Korean hemorrhagic fever, and the virus was named Hanta after the Hantaan River of Korea. Over the ensuing years, several other etiologic agents of HFRS such as the Seoul, Puumala, and Dobrava viruses, were discovered across Europe and Asia.

Though antigenic evidence of Hantavirus remains widespread among rodents across the United States,only a handful of cases of HFRS was ever identified in the states.

Species Of Rodents Responsible For Hantavirus

Hantavirus hemorrhagic fever with renal syndrome (HFRS) is a group of clinically similar illnesses caused by species of hantaviruses from the family Hantaviradae, in the order Bunyavirales. It is also known as Korean hemorrhagic fever and epidemic hemorrhagic fever. The species that cause HFRS include Hantaan orthohantavirus , Dobrava-Belgrade orthohantavirus , Saaremaa virus, Seoul orthohantavirus Puumala orthohantavirus , and other orthohantaviruses. It is found in Europe, Asia, and Africa. Of these species, Hantaan River virus and Dobrava-Belgrade virus cause the most severe form of the syndrome and have the highest morbidity rates. When caused by the Puumala virus, , it is also called nephropathia epidemica. This infection is known as sorkfeber in Swedish and myyräkuume in Finnish (vole fever). In Norway, it is called musepest (mouse plague).

Both hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS) appear to be immunopathelogic , and inflammatory mediators are important in causing the clinical manifestations.

Signs and symptoms

Symptoms of HFRS usually develop within 1 to 2 weeks after exposure to infectious material, but in rare cases, they may take up to 8 weeks to develop. In Nephropathia epidemica, the incubation period is three weeks. Initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea, and blurred vision. Individuals may have flushing of the face, inflammation or redness of the eyes, or a rash. Later symptoms can include low blood pressure, acute shock, vascular leakage, and acute kidney failure, which can cause severe fluid overload.

When to See Your Doctor

If you have unexplained fever, body aches, abdominal pain, diarrhea, headaches, dry cough or severe breathing difficulty, you should see a healthcare provider. This is especially true if you live in the southwestern US and are exposed to large rodent populations, their nesting material and waste.

The severity of the disease varies depending upon the virus causing the infection. Hantaan and Dobrava virus infections usually cause severe symptoms, while Seoul, Saaremaa, and Puumala virus infections are usually more moderate. Complete recovery can take weeks or months.

The course of the illness can be split into five phases:

This syndrome can also be fatal. In some cases, it has been known to cause permanent renal failure.

Transmission

Transmission by aerosolized rodent excreta still remains the only known way the virus is transmitted to humans. In general, droplet and/or fomite transfer has not been shown in the hantaviruses in either the pulmonary or hemorrhagic forms.

For Nephropathia epidemica, the bank vole is the reservoir for the virus, which humans contract through inhalation of aerosolised vole droppings.

Diagnosis

HFRS is difficult to diagnose on clinical grounds alone and serological evidence is often needed. A fourfold rise in IgG antibody titer in a 1-week interval, and the presence of the IgM type of antibodies against hantaviruses are good evidence for an acute hantavirus infection. HFRS should be suspected in patients with acute febrile flu-like illness, kidney failure of unknown origin and sometimes liver dysfunction.

Treatment

There is no cure or vaccine for HFRS. Treatment involves supportive therapy including renal dialysis. Treatment with ribavirus in China and Korea, administered within 7 days of onset of fever, resulted in a reduced mortality as well as shortened course of illness.

Prevention

Rodent control in and around the home remains the primary prevention strategy, as well as eliminating contact with rodents in the workplace and campsite. Closed storage sheds and cabins are often ideal sites for rodent infestations. Airing out of such spaces prior to use is recommended. Avoid direct contact with rodent droppings and wear a mask to avoid inhalation of aerosolized rodent secretions.

Epidemiology

HFRS is primarily a Eurasian disease, whereas HPS appears to be confined to the Americas. The geography is directly related to the indigenous rodent hosts and the viruses that coevolved with them.

Although fatal in a small percentage of cases, nephropathia epidemica is generally milder than the HFRS that is caused by hantaviruses in other parts of the world.

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